A conventional electrically tunable focusing liquid crystal lens is disclosed by H. C. Lin, M. S. Chen, and Y. H. Lin in an article entitled “A Review of Electrically Tunable Focusing Liquid Crystal Lenses,” Transactions on Electrical and Electronic Materials 12(6), 234-240 (2011).
A conventional polarizer free liquid crystal lens is disclosed by Y. H. Lin and H. S. Chen in an article entitled “Electrically tunable-focusing and polarizer-free liquid crystal lenses for ophthalmic applications,” Opt Express 21(8), 9428-9436 (2013).